Supported vanadium catalyst for polymerization of olefins and a process of preparing and using the same

ABSTRACT

This invention relates to a supported vanadium-alumoxane catalyst for use in gas and liquid polymerization of olefins. The invention particularly relates to the use of silica gel containing from about 6 to about 20 percent by weight adsorbed water as the catalyst support material. The particle size of the silica gel is generally between about 0.1 and 200.0 μu. Such silica gel may be safely added to a trialkylaluminum solution to form by direct reaction with the adsorbed water content of the silica gel catalyst support material the alumoxane cocatalyst component of the catalyst system. An alumoxane coated silica gel is formed to which a vanadium compound is added and the resulting material dried to a free flowing powder. The dry free flowing powder may then be used as a supported vanadium alumoxane catalyst complex for the polymerization of olefins. Resins produced from such processes have a broad molecular weight distribution suitable in blow molding for the fabrication of household and industrial containers.

This invention relates to a supported vanadium alumoxane catalystcomplex. The catalyst support is a silica gel containing from about 6 toabout 20 per cent by weight adsorbed water. Such silica gel is added toa trialkylaluminum solution to form, by direct reaction of thetrialkylaluminum with the adsorbed water content of the silica gel, analumoxane coated silica gel. A vanadium containing compound is added tothe alumoxane coated silica gel and the resulting material dried to afree flowing powder. The dry free flowing powder comprising a supportedvanadium alumoxane catalyst complex can be used in gas and liquid phaseolefinic polymerization processes to produce resins with a broadmolecular weight distribution. Further, when used in such processes thecatalyst complexes of this invention do not require the use of ahydrogenated alkane promoter as with other vanadium-containing olefinpolymerization catalysts in order to exhibit a sufficiently high levelof productivity as to be commercially useful.

BACKGROUND TO THE INVENTION

Catalysts for the polymerization of olefins comprising either (a) ametallocene-alumoxane complex or (b) a complex formed from transitionmetal (IVB, VB) and organoaluminum compounds are known in the art.Australian Patent No. 220436 discloses a catalyst comprising thereaction product of a metallocene [bis(cyclopentadienyl)] vanadium saltwith a variety of aluminum alkyl compounds. As illustrated by the art,when cocatalyzed with an aluminum alkyl, although a metallocene willexhibit some catalytic activity, the degree of activity is too low to becommercially useful.

The production of a metallocene-based catalyst of commercially usefulactivity requires the use of an alumoxane as the cocatalyst. Heretofore,the requirement for an alumoxane cocatalyst has entailed extra costand/or production procedures for preparing a metallocene-based catalyst.An alumoxane is formed from the highly rapid and exothermic reaction ofan aluminum alkyl with water. Because of the extreme violence of thereaction the alumoxane component has previously been separately preparedby one of two general methods. In one method, referred to as the "wetsolvent production method", extremely finely divided water, such as inthe form of a humid solvent, is added to a solution of aluminum alkyl inbenzene or other aromatic hydrocarbon. The production of an alumoxane bythis process requires use of explosion-proof equipment and very closecontrol of the reaction conditions in order to reduce potential fire andexplosion hazards. For this reason, it has been preferred to producealumoxane by the second method, often referred to as the "hydrated saltmethod". In this process, an aluminum alkyl is reacted with a hydratedsalt, such as hydrated copper sulfate. A slurry of finely divided coppersulfate pentahydrate and toluene is formed and mantled under an inertgas. Aluminum alkyl is then slowly added to the slurry with stirring andthe reaction mixture is maintained at room temperature for 24 to 40hours during which a slow hydrolysis occurs by which alumoxane isproduced. Although the production of alumoxane by the hydrated saltmethod significantly reduces the explosion and fire hazard inherent inthe wet solvent production method, production of the alumoxane mustnevertheless be carried out separately. Further, before the alumoxanecan be used for the production of an active catalyst complex andhydrated salt reagent must be separated from the alumoxane to prevent itfrom becoming entrained in the catalyst complex and thus contaminatingany polymer produced therewith. The process is slow and produceshazardous wastes that create waste disposal problems.

In certain instances wherein a filled polyolefin resin is to be producedthe requisite alumoxane cocatalyst may be produced by reacting atriakylaluminum with the filler material then forming themetallocene-alumoxane catalyst complex on the surface of the fillermaterial. For example, U.S. Pat. No. 4,431,788 discloses a catalystcomprising a metallocene complex and starch. These catalysts areproduced by a reacting a trialkylaluminum with starch particles having amoisture content below 7 weight percent. The starch partices are thentreated with a metallocene to form metallocene-alumoxane catalystcomplex on the surface of the starch partices. An olefin is thenpolymerized about the starch particles by solution or suspensionpolymerization procedures to form a free-flowing composition ofpolyolefin-coated starch particles.

Unlike the case of metallocene-based catalysts, the art teaches that thecocatalyst for a catalyst containing a vanadium component (such as VCl₄or VOCl₃) should be an aluminum akyl. In particular, U.S. Pat. Nos.4,579,835; 4,607,019 and 4,607,751, disclose the production of a silicagel supported vanadium-based catalyst, and specify that the silica gelmust first be dehydrated to remove any water and to reduce theconcentration of surface hydroxyl groups which otherwise could reactwith the aluminum alkyl.

To obtain a degree of productivity useful for commercial production ofpolyolefins, such prior art supported vanadium catalyst further requirethe presence of a "promoter" in the polymerization reactor. Halogenatedalkanes, such as chloroform or Freon 11, are typically used as apromoter to elevate the productivity of the prior art vanadium basedcatalyst composition to a level sufficient for commercial production. Itis believed that the promoter oxidized the vanadium cation to the higher(III) oxidation state which renders the catalyst its most active,whereas the aluminum alkyl co-catalyst reduces the vanadium cation tothe less active (II) oxidation state during polymerization. Therefore,continuous supply of promoter during polymerization has been required tomaintain the requisite concentration of vanadium (III) in order tomaintain productivity of the catalyst at a useful level.

Consequently, polymerization processes catalyzed by the prior artvanadium-aluminum alkyl complexes suffer several serious disadvantages.Since the prior art vanadium catalysts are effective only in thepresence of a promoter, the process of preparing the polyolefinsrequires extra procedural steps. In particular, the introduction ofpromoter and vanadium-aluminum catalyst requires distinct steps.Further, the operator must constantly monitor the level of promoter inthe reactor in order to obtain efficiency of the prior are vanadiumcatalyst complex.

The most effective promoters for the prior art vanadium catalystcomplexes are, generally, halogenated alkanes. Suitable promoters, suchas chloroform and dichlorodifluoroethane, leave an undesired halogenresidue in the polymeric end-products. Consequently, use of halogenpromoters with the prior art vanadium catalyst complexes may render thepolyolefin product highly corrosive or require post polymerizationtreatment of the polymer product for removal of halogen residue.

Resins produced from the supported vanadium catalysts are typicallycharacterized by a broader molecular weight distribution (MWD), comparedto resins made by other transition metal catalysts. Such resins aresuitable for application in blow molding.

It would be advantageous to develop a vanadium based supported catalystuseful for the polymerization of olefins which does not require theassistance of a promoter and which exhibits high activity andefficiency. Further, it would be most desirable to produce a catalystcapable of rendering a non-corrosive resin having a broad molecularweight distribution.

It would further be most desirable to devise an economical procedurewhereby such catalysts could be safely and economically produced.

SUMMARY OF THE INVENTION

This invention discloses a novel vanadium based supported catalystuseful in the production of polyolefins of broad molecular weightdistribution ("MWD"). Such resins have particular applicability in blowmolding operations. Further, the catalyst of this invention exhibitshigh productivity in the absence of a halogenated promoter.

The catalyst system of this invention comprises a vanadium compoundwhich is cocatalyzed with an alumoxane which is formed by the reactionof a trialkylaluminum with an undehydrated silica gel. The catalystsystem of this invention utilizes as the support material silica gel.Desirably, the silica particles will have a surface area in the range ofabout 10 m² /g to about 700 m² /g, preferably about 100-500 m² /g anddesirably about 200-400 m² /g, a pore volume of about 3 to about 0.5cc/g and preferably 2-1 cc/g and an adsorbed water content of from about6 to about 20 weight percent, preferably from about 7 to about 15 weightpercent. The particle size of the silica is generally from about 0.1 toabout 200μ. The silica particles referenced above are hereinafterreferred to as undehydrated silica gel.

The silica gel supported vanadium alumoxane catalyst is prepared byadding the undehydrated silica gel to a stirred solution oftrialkylaluminum in an amount sufficient to provide a mole ratio oftrialkylaluminum to water of from about 3:1 to about 1:2, preferably1.2:1 to about 0.8:1, thereafter adding to this stirred solution avanadium containing compound in an amount sufficient to provide analuminum to vanadium ratio of from about 1000:1 to 1:1, preferably fromabout 300:1 to about 10:1, most preferably from about 150:1 to about30:1; removing the solvent and drying the solids to a free flowingpowder. Drying can be obtained by modest heating or vacuum.

The dried free flowing powder comprises a vanadium alumoxane catalystcomplex adsorbed upon the surface of the silica gel support. Thesupported catalyst complex has an activity sufficient for use as apolymerization catalyst for polymerization of olefins under either gasor liquid phase polymerization.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present invention is directed towards a supported catalyst systemfor use in either gas phase or liquid phase polymerization of olefins,particularly the polymerization of ethyene to high molecular weightpolyethylenes such as linear low density polyethylene (LLDPE) and highdensity polyethylene (HDPE). The polymers are intended for fabricationinto household and industrial containers by blow molding.

The active catalyst complex comprises a vanadium compound and analumoxane adsorbed onto the surface of a silica gel support material.Alumoxanes are oligomeric aluminum compounds represented by the generaformula (R--Al--O)_(y) which is believed to be a cyclic compound andR(R--Al--O--)_(y) AlR₂, which is a linear compound. In the generalformula, "R" is a C₁ -C₁₀ alkyl group such as, for example, methyl,ethyl, propyl, butyl, and pentyl and "y" is an integer from 2 to about30 and represents the degree of oligomerization of the alumoxane.Preferably, "R" is methyl and "y" is about 4 to about 25 and mostpreferably 6-25. Generally, in the preparation of alumoxanes from, forexample, the reaction of trimethyl aluminum and water, a mixture oflinear and cyclic compounds is obtained. Generally, an alumoxane havinga higher degree of oligomerization will, for a given vanadium compound,produce a catalyst complex of higher activity than will an alumoxanehaving a lower degree of oligomerization. Hence, the procedure by whichalumoxane is produced by direct reaction of a trialkylaluminum with anundehydrated silica gel should insure the conversion of the bulkquantity of the trialkylauminum to an alumoxane having a high degree ofoligomerization. In accordance with this invention the desired degree ofoligomerization is obtained by the order of addition of reactants asdescribed hereinafter.

The preferred vanadium compounds which may be usefully employed in thepreparation of the vanadium containing catalyst component of thisinvention are well known in the art and may be represented by theformulas: ##STR1## wherein:

m is 0-3;

n is 0 or 3-4;

p is 2-3;

q is 0 or 2-3;

x and y are 1-2, x≠y;

R is a C₁₋₈ acyclic or cyclic hydrocarbon radical, preferably free ofethylenic unsaturation;

R' is acetylacetonate;

X is --Cl or --Br; and

B is a Lewis base capable of forming hydrocarbon-soluble complexes withVX₃ such as ether. Especially preferred as R are methyl, ethyl, propyl,iso-propyl, butyl, n-butyl, i-butyl, t-butyl, pentyl, hexyl, octyl,cyclohexyl, phenyl, benzyl, dimethyl phenyl, and naphthyl groups.

Illustrative, but non-limiting examples of the vanadium compounds arevanadyl trichloride, vanadyl tribromide vanadium tetrachloride, vanadiumtetrabromide, vanadium tetrabutoxide, vanadium trichloride, vanadiumtribromide, vanadyl diacetylacetonate, vanadium triacetylacetonate,vanadyl dichloroacetylacetonate, vanadyl chlorodiacetylacetonate, andvanadium trichloride or vanadium tribromide complexed withtetrahydrofuran.

Heretofore the alumoxane component of the active catalyst complex forpolymerization of olefins has been separately prepared then added assuch to a catalyst support material which is then treated with a metalcompound to form the active catalyst complex. One procedure heretoforeemployed for preparing the alumoxane separately is that of contactingwater in the form of a moist solvent with a solution of trialkylaluminumin a suitable organic solvent such as benzene or aromatic hydrocarbon.As before noted this procedure is attendant with fire and explosionhazards which requires the use of explosion-proof equipment andcarefully controlled reaction conditions. In an alternative methodheretofore employed for the separate production of alumoxane, analuminum alkyl is contacted with a hydrated salt, such as hydratedcopper sulfate. The method comprised treating a dilute solution ofaluminum alkyl in, for example, toluene, with a copper sulfatepentahydrate. A slow, controlled hydrolysis of the aluminum alkyl toalumoxane results which substantially eliminates the fire and explosionhazard but with the disadvantage of the creation of hazardous wasteproducts that must be disposed of and from which the alumoxane must beseparated before it is suitable for use in the production of an activecatalyst complex. Separate production of the alumoxane component byeither procedure is time consuming and costly. Correspondingly, the useof a separately produced alumoxane greatly increases the cost ofproducing an alumoxane catalyst.

In accordance with the present invention the alumoxane component of thecatalyst complex is prepared by direct reaction of a trialkylaluminumwith the material utilized as the catalyst support, namely anundehydrated silica gel. Silica useful as the catalyst support is thatwhich has an average particle size between about 0.1μ and about 200μ(1μ=1.10⁻⁶ m); a surface area in the range of about 10 to about 700 m²/g, preferably about 100-500 and desirably about 200-400 m² /g; a porevolume of about 3 to about 0.5 cc/g and preferably 2-1 cc/g; and anadsorbed water content of from about 6 to about 20 weight percent,preferably from about 7 to about 15 weight percent.

Such undehydrated silica gel is added over time, about a few minutes, toa stirred solution of trialkylaluminum, preferably trimethylaluminum ortriethylaluminum, in an amount sufficient to provide a mole ratio oftrialkylaluminum to water of from about 3:1 to 1:2, preferably about1.2:1 to 0.8:1. The solvents used in the preparation of the catalystsystem are inert hydrocarbons, in particular a hydrocarbon that is inertwith respect to the catalyst system. Such solvents are well known andinclude, for example, isobutane, butane, pentane, hexane, heptane,octane, cyclohexane, methylcyclohexane, toluene, xylene and the like.Each alkyl group in the trialkylaluminum independently contains 1 to 10carbon atoms. Also suitable for use as the trialkylaluminum aretripropyl aluminum, tri-n-butyl aluminum, tri-isobutyl aluminum,tri(2-methylpentyl) aluminum, trihexyl aluminum, tri-n-octyl aluminum,and tri-n-decyl aluminum.

Upon addition of the undehydrated silica gel to the solution oftrialkylaluminum, the water content of the silica gel controllablyreacts with the trialkylaluminum to produce an alumoxane which isdeposited onto the surface of the silica gel particles. Although thereaction of the trialkylaluminum with the water content of the silicagel proceeds relatively quickly (generally within about 5 minutes), itdoes not occur with the explosive quickness of that which occurs withfree water. The reaction may be safely conducted in conventional mixingequipment under a mantle of inert gas.

Thereafter a vanadium compound is added to the stirred suspension ofalumoxane silica gel product in an amount sufficient to provide a moleratio of aluminum to vanadium of from about 1000:1 to about 1:1,preferably from about 300:1 to about 10:1 and most preferably from about150:1 to about 30:1. The vanadium compound is preferably added to thereaction mixture in the form of a solution. The solvent can be any ofthe well-known inert hydrocarbon solvents such as those employed in theproduction of the alumoxane above. The mixture is stirred for about 30minutes to about one hour at ambient or at an elevated temperature ofabout 75° C. to permit the vanadium compound to undergo completecomplexing reaction with the adsorbed alumoxane. Thereafter, the solventis removed by filtering or evaporation, and the residual solids aredried to a free flowing powder. The dried free flowing powder comprisesa vanadium-alumoxane catalyst complex with a silica gel support ofsufficiently high catalytic activity for use in the polymerization ofolefins. The average particle size of the free flowing powder isequivalent to that of the particle size of silica employed in theproduction of the catalyst support material.

The order of addition between the undehydrated silica gel and thetrialkylaluminum is important with regards to the activity of thesupported catalyst which results upon addition of the vanadium compound.A supported catalyst composition of little or no activity resultswherein a trialkylaluminum is added to a stirred solvent suspension ofundehydrated silica gel. It has been found that to prepare a supportedcatalyst composition of acceptable or high activity the order of mixingmust be one wherein the undehydrated silica gel is added to a stirredsolution of the trialkylaluminum. It is believed that this order ofmixing forces the trialkylaluminum to undergo reaction in the context ofa transient localized excess of trialkylaluminum compared to a transientlocalized deficiency of water. Under a mixing condition which slowlyadds undehydrated silica gel to a stirred solution of trialkylaluminum,the bulk content of the trialkylaluminum converts to an alumoxane with adegree of oligomerization of about 6-25 (y=6-25). Production of analumoxane with this degree of oligomerization results in a finalvanadium-alumoxane catalyst complex of useful or high activity. Areverse order of mixing, that is, addition of a trialkylaluminum to astirred solvent suspension of undehydrated silica gel yields a catalystwhich has a poor degree of catalytic activity.

In addition to the importance of proper mixing order in achieving asupported catalyst of useful activity, it has also been observed thatthe water content of the undehydrated silica gel influences finalcatalyst activity. Hence the undehydrated silica gel should have anadsorbed water content of from about 6 to about 20 weight percent.Preferably the adsorbed water content should be from about 7 to about 15weight percent.

Further influencing the degree of activity attained in the finalsupported catalyst complex is the mole ratio of trialkylaluminum to theadsorbed water content of the undehydrated silica gel. The quantities oftrialkylaluminum employed should, in comparison to the quantity ofundehydrated silica gel of specified adsorbed water content, be selectedto provide a mole ratio of trialkylaluminum to water of from about 3:1to about 1:2, preferably from about 1.5:1 to about 0.8:1, and morepreferably from about 1.2:1 to about 0.8:1. It has been observed thatfor a given vanadium compound, a maximum catalyst activity is generallyobserved in the trialkylaluminum to water mole ratio range of about1.2:1 to about 0.8:1. Depending upon the particular trialkylaluminumselected for use, commercially acceptable catalyst activities areexhibited in the trialkylaluminum to water mole ratio range of about 3:1to about 1:2.

Also influencing the cost of production and the level of catalyticactivity obtained in the final supported catalyst complex is the moleratio of aluminum to vanadium of the vanadium compound. The quantity ofvanadium compound added to the alumoxane adsorbed silica gel solidsshould be selected to provide an aluminum to vanadium mole ratio of fromabout 1000:1 to about 1:1, preferably from about 300:1 to about 10:1,and most preferably from about 150:1 to about 30:1. From the standpointof economic considerations it is desirable to operate in the lowerranges of the aluminum to vanadium mole ratio in order to minimize thecost of catalyst production. The procedure of this invention is onewhich provides the maximum conversion of the trialkylaluminum componentto the most efficacious form of alumoxane, hence permits the safeproduction of a supported vanadium alumoxane catalyst of useful activitywith low quantities of the costly trialkylaluminum component.

The molecular weight of the polymers produced in the presence of thecatalyst system disclosed herein can be controlled by means well knownin the art. In a gas or liquid phase polymerization of olefins, hydrogenis employed in order to control the desired molecular weight of thepolymeric end product. Polymerization proceeds generally at atemperature between 25° and 150° C.

The polymers prepared with the catalyst complex and by the method ofthis invention are homopolymers of ethylene and copolymers of ethylenewith higher alpha-olefins having from 3 to about 18 carbon atoms andpreferably 3 to 8 carbon atoms. Illustrative of the higher alpha-olefinsare propylene, butene-1, hexene-1, and octene-1. Elastomers can also beprepared by copolymerizing ethylene with propylene and dienes,preferably those dienes having up to 20 carbon atoms.

EXAMPLES

Example 1 illustrates the preparation of a VOCl₃ -triethylaluminumcatalyst supported on a dehydrated silica gel. Catalyst Tests A and Billustrate the performance of the catalyst of Example 1 in thepolymerization of ethylene in the presence of and absence of ahalogenated hydrocarbon, respectively.

Examples 2-5 illustrate the preparation of the supportedvanadium-alumoxane catalyst complexes of this invention wherein thealumoxane catalyst component was formed by reaction of atrialkylaluminum with an undehydrated silica gel. Catalyst Tests C and Dillustrate the performance of the catalyst of Example 2-5.

Example 1 (Comparative)

Silica gel (5.0 g, Davison 948 silica gel, dehydrated at 500° C.) wasadded to a vial containing 20 ml of hexane. Four and three-tenths (4.3)milliliters of triethylaluminum/heptane solution (1.58M) was thencharged into the vial. The resulting mixture was allowed to react atambient temperature for 30 minutes. Thereafter 2.4 ml of neatbenzoylchloride was added to the vial and the reaction was permitted toproceed at room temperature for one hour. To the vial was then added 2.0ml of a hexane solution of VOCl₃ (0.7M). After allowing this mixture toreact at ambient temperature for one hour and permitting the resultingsolids to settle, the supernatant was decanted from the vial. Themixture was then stirred for 10 minutes after the addition to the vialof 20 ml. of hexane. After decantation of the supernatant, the catalystwas dried to a free flowing powder by nitrogen purging.

Catalyst Test A

A freshly cleaned 2.2 liter autoclave was heated to 60° C. and flushedwith nitrogen for 30 minutes. After cooling to room temperature, 0.6 mlof triethylaluminum in a solution of heptane (1.67M) and 0.9 ml of(liquid) Freon-11 were charged into the reactor containing 850 ml ofdried, oxygen-free hexane. After heating the reactor to 85° C., 31 mmoleof hydrogen and 100 ml of 1-hexene were added. The reactor was thenpressurized by adding thereto 150 psig of ethylene gas. Seventy-five(75) mg of the catalyst of Example 1 (Comparative) was then injectedinto the reactor. After a reaction time of 40 minutes, 83 g ofpolyethylene was recovered.

Catalyst Test B

The procedure of Example 2 was followed with the exception that noFreon-11 was added to the reactor. One (1) g of polyethylene wasrecovered.

Example 2

Undehydrated silica gel was employed in accordance with the procedure ofthis invention to prepare a silica gel supported VOCl₃ methylalumoxanecatalyst complex, as follows:

A one liter three neck flask equipped with a magnetic stirring bar wascharged with 170 ml of dried and degassed heptane. One hundred-thirty(130) milliliters of trimethylaluminum/heptane solution (1.5M) was thencharged into the flask. A clear solution was formed. Thereafter 50 g ofundehydrated silica gel (Davison 948 with average particle size of 50μ)which contains 8.5 weight percent water was added slowly into the flaskthrough a solids addition vessel. The resulting mixture was allowed toreact under stirring at ambient temperature for 1 hour. The volatilesolvent was then removed by nitrogen purging while the flask was heatedto a drying temperature of 75° C. in an oil bath until the contents ofthe flask became solid. The mixture was then dried to a free flowingpowder by vacuum drying at ambient temperature. Thereafter, 5.0 g of thefree flowing powder was transferred to a 125 ml vial. Added sequentiallyto the vial were 30 ml of hexane and 2.0 ml of VOCl₃ dissolved in hexane(0.7M). The resulting mixture was allowed to react at ambienttemperature for 30 minutes. The solvent was then removed by nitrogenpurging and the catalyst solids isolated by vacuum evaporation.

Example 3

The procedure of Example 2 was followed with the exception that 130 mlof triethylaluminum/heptane solution (1.5M) was charged into the driedthree-neck flask.

Example 4

Undehydrated silica gel was employed in accordance with the procedure ofthis invention to prepare a silica gel supported VOCl₃ methylalumoxanecatalyst complex, as follows:

A one liter three neck fast equipped with a magnetic stirring bar wascharged with 300 ml of dried and degassed heptane. Two hundred-sixty(260) milliliters of trimethylaluminum/heptane solution (1.5M) was thencharged into the flask. Thereafter 100 g of undehydrated silica gel(Davison 948) which contained 8.7 weight percent water was added slowlyinto the flask through a solids addition tube. The resulting mixture wasallowed to react under stirring at ambient temperature for 1 hour.Thereafter 40.0 ml of VOCl₃ dissolved in hexane (0.7M) was added to theflask and the resulting mixture was allowed to react under stirring for30 minutes at ambient temperature. The volatile solvent was then removedby nitrogen purging while the flask was heated to a temperature of 65°C. in an oil bath until the contents of the flask became solid. Themixture was then dried to a free flowing powder by vacuum drying atambient temperature.

Example 5

100 g of undehydrated silica gel (Davison 948) which contained 7.4weight percent water was added into a three-neck dried flask containing260 ml of triethylaluminum/heptane solution (1.5M) and 360 ml ofheptane, and thereafter the mixture was dried. The dried mixture wasreslurried with 400 ml of hexane followed by the addition of 40.0 ml ofVOCl₃ dissolved in hexane (0.7M). The mixture was then dried to a freeflowing powder.

Catalyst Test C

The activity of the catalyst powders of Examples 2 to 5 were determinedat ambient temperature and 5 psig ethylene pressure by the followingprocedure. To a 150 milliliter vial, equipped with magnetic stirrer, wascharged 4 grams of catalyst composition. At ambient temperature ethylenegas at 5 psig was fed into the vial. Polymerization of the ethylene wasallowed to proceed for one hour. The yield of polyethylene obtained witheach catalyst composition is reported in Table I.

                  TABLE I                                                         ______________________________________                                        CATALYST TEST A RESULT                                                                      Amount                                                                        Polyethylene                                                    Catalyst      Formed, g                                                       ______________________________________                                        Example 2     6.8                                                             Example 3     6.1                                                             Example 4     7.4                                                             Example 5     3.6                                                             ______________________________________                                    

Catalyst Test D

The activity of the catalyst of Example 4 was determined in a continuousfluid bed gas phase polymerization reactor at 300 psig total pressureand 165° F. Ethylene was copolymerized with hexene-1.

During the polymerization, ethylene, hexene-1, hydrogen and nitrogenwere continuously fed into the reactor to maintain the followingconstant gas concentrations:

    ______________________________________                                        Nitrogen           62.0 mole percent                                          Ethylene           30.0 mole percent                                          Hexene-1           2.0 mole percent                                           Hydrogen           6.0 mole percent                                           ______________________________________                                    

The velocity of the gas in the reactor was 0.7 ft./sec. Catalyst wasperiodically injected into the reactor as required to maintain aconstant production rate of about 200 g polymer/hr. Polymer product wasperiodically removed from the reactor through a valve to maintain aconstant bed weight in the reactor.

The polymerization reaction was conducted for more than 24 hours. TableII lists properties of the polymer produced.

                  TABLE II                                                        ______________________________________                                        Hours After Yield                   Density                                   Steady State                                                                              g/hr    Mw        Mw/M  g/cc                                      ______________________________________                                        12          213     --        --    0.924                                     15          187     --        --    0.927                                     18          215     86,000    60.6  0.923                                     ______________________________________                                    

The invention has been described with reference to its preferredembodiments. From this description, a person of ordinary skill in theart may appreciate changes that could be made in the invention which donot depart from the scope and spirit of the invention as described aboveand claimed hereafter.

I claim:
 1. A supported non-metallocene vanadium alumoxane catalystcomplex, produced by:(a) adding an undehydrated silica gel to a stirredsolution of a trialkylaluminum in an amount sufficient to provide a moleratio of trialkylaluminum to water of from about 3:1 to about 1:2 andallowing the mixture to react; (b) adding a non-metallocene vanadiumcompound to the reacted mixture; (c) removing the solvent; and (d)drying the solids to form a free flowing powder.
 2. The catalyst ofclaim 1, wherein said undehydrated silica gel has a water content offrom about 6 to about 20 weight percent.
 3. The catalyst of claim 1,wherein the mole ratio of aluminum to vanadium in said vanadium compoundis from about 1000:1 to about 1:1.
 4. The catalyst of claim 2, whereinsaid undehydrated silica gel has a water content of from about 6 toabout 20 weight percent and the mole ratio of trialkylaluminum to wateris from about 3:1 to about 1:2.
 5. The catalyst of claim 4, wherein themole ratio of aluminum to vanadium in said vanadium compound is fromabout 1000:1 to about 1:1.
 6. The catalyst of claim 5, wherein thetrialkylauminum is trimethylauminum or triethylaluminum.
 7. The catalystof claim 6, wherein said undehydrated silica gel has a surface area offrom about 200 to about 400 m² /g, a pore volume of from about 1 toabout 2 cc/g and a particle size from about 0.1 to 200μ.
 8. The catalystof claim 1, wherein said vanadium compound is selected from the groupconsisting of: ##STR2## wherein: m is 0-3;n is 0 or 3-4; p is 2-3; q is0 or 2-3; x and y are 1-2, x≠y; R is a C₁ -C₈ hydrocarbon radical; R' isacetylacetonate; X is --Cl or --Br; and B is a Lewis base capable offorming hydrocarbon-soluble complexes with VX₃.
 9. The catalyst of claim8, wherein said vanadium compound is selected from the group consistingof vanadyl trichloride, vanadyl tribromide, vanadium tetrachloride,vanadium tetrabromide, vanadium tetrabutoxy, vanadium trichloride,vanadium tribromide, vanadyl acetylacetonate, vanadium acetylacetonate,vanadyl dichloroacetylacetonate, vanadyl chlorodiacetylacetonate, andvanadium trichloride or vanadium tribromide complexed withtetrahydrofuran.
 10. The catalyst of claim 9 wherein said vanadiumcompound is vanadyl tricholoride.